The invention relates to agricultural planters, such as hoe openers and seeding tools used in farming operations to distribute seeds into soil. Generally, openers are towed behind a tractor via a mounting bracket secured to a rigid frame of the tractor. These openers may include a ground engaging tool or opener that forms a seeding path for seed deposition into the soil. The ground opener is used to break the soil to enable seed deposition. After the seed is deposited, the opener may be followed by a packer wheel that packs the soil on top of the deposited seed. The packer wheel may be rigidly mounted behind the opener via a structural member or rear frame. Thus, the opener and packer wheel generally move together with the same upward and downward motion.
Unfortunately, existing openers do not adequately address the need to accommodate height variation over terrain during seeding or transportation without seeding. It is generally undesirable to pull the hoe opener through soil when merely transporting the opener from one location to another. In addition, during seeding, existing openers do not provide adequate vertical motion of the opener and related assembly without compromising the load on the opener and packer wheel. As a result, variations in the terrain can result in substantial changes in the packing force (e.g., normal force) of the packer wheel on the terrain being seeded by the opener and the draft force of the terrain on the opener. The variable force on the opener can result in loss of control over seeding depth. More specifically, this variation in packing and opener force can result in non-uniform seeding depths and packing density in the terrain being seeded by the planter.
Existing openers also require substantial force to raise the planter row unit, including the opener assembly and packing wheel. This results in the use of large hydraulic cylinders to raise the apparatus, due to the overall length and weight of each planter row unit. This hydraulic equipment is costly and takes resources (i.e. hydraulic power) from other portions of the tractor and planter unit.
There is a need, therefore, for improved arrangements in precision hoe openers and planters that improve accuracy of the seeding operation. There is a particular need for planters and openers that apply forces to the opener and the packing wheel to improve seeding depth and accuracy.